Dual mode mobile phones enable telephony connections by circuit-switched networks like GSM or by packet-switched network like a WLAN internet access. A user using the WLAN internet access may wish to access value-added services like location based services, download of ring tones and voicemail. To enable such services the IMS (IP Multimedia Subsystem) is introduced as an architectural framework for delivering IP multimedia services to end-users. IMS is used for evolving mobile networks beyond GSM and enables third party providers an easy integration of their services.
The Mobile, Fixed, Fixed Mobile Convergence operators start to extend their service offers with services provided via this IP-based Multimedia Subsystem (IMS) defined in 3GPP (3rd Generation Partnership Project) and TISPAN (Telecoms R. Internet converged Services Protocols for Advanced Networks Standards). U.S. Pat. No. 6,859,651 shows an exemplary IMS system and how a client registers to the IMS system.
For a user that uses the IMS system for the first time, provisioning of the IMS user data requires a significant effort. This slows down the introduction of new services.